Depth of field scale is it necessary?

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ian-83

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Been looking to get into taking landscape photography a bit more and first on my list is a good tripod, but having a look about at a few articles about technique etc,. I have noticed a general suggestion is to focus about 1/3rd of the way into the scene. I currently using 4/3rds system but my lens has no depth of field scale on the lens. Will this cause issues? I have seen on things like Canon and Nikon lenses they have the depth of field scale on the lens which I guess makes setting up the lens in manual focus easier?
 
The only issue I can see is a trying to use the hyper focal distance technique. Focusing in about a third of the photo can be guessed using try and error rather than using the focus scale. It's most liking a technique taken from the depth of field is sharp between one third in front of the focus point and two thirds behind the focus point rather 50-50.
 
I need them. I just cannot get a hang of dof. That's why I have bought the Batis lenses. At least they give me a good idea of the dof.
 
ian-83 said:
I have noticed a general suggestion is to focus about 1/3rd of the way into the scene.
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I have never understood this. If you have distant mountains, perhaps three miles away, 1/3 in is one mile.


Steve.
 
Steve Smith said:
I have never understood this. If you have distant mountains, perhaps three miles away, 1/3 in is one mile.


Steve.
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As I understand it, it is 1/3 of the scene, not 1/3 of the distance to the farthest point (if there is sky then that gets a bit silly). Because of perspective the near foreground will occupy a larger part of the scene than distant objects and so you will be focusing on something in the near foreground. Obviously hyperfocal distance is a better guide and for a given lens/aperture it may well be better to just know that you focus on an object at N feet.
 
sirch said:
As I understand it, it is 1/3 of the scene, not 1/3 of the distance to the farthest point (if there is sky then that gets a bit silly
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Yes. That would effectively be a third of infinity if you are including the sun or other stars!

A third of the way into the scene is affected by other factors, primarily height of the camera and the slope of the land. Also the placing of the horizon in the frame. Much better to learn depth of field and hyperfocal settings.


Steve.
 
Depth of field calculations and scales have always been approximate. As they are based on a circle of confusion that is also chosen as an approximation for sharpness.
In reality a lens is only fully sharp at one distance when focused, sharpness falls off progressively either side of that distance. Depth of field gives the impression that enerything between two distances is equally sharp. It is not. The fall off is just considered sharp enough for small enlargements.

In reality distant objects can be affected to a far greater extent by atmospheric haze and risidual camera shake, both of which are magnified at large distances.
 
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For me you will have plenty of more important things to worry about than a dof scale. Start with a decent composition with good light and you will be more than half way there!
 
There are photography apps with Dof calculators in. Free ones to try out too.

This should be built in to cameras in a clever way with an enhanced preview like focus peaking.
 
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You don't NEED them, as with many camera features they're nice aids to have but won't stop you taking a picture. With m4/3 you can use the magnified view to check that your DOF covers where you want it to.
 
Also forget photography "rules". Focus on what you want to focus on and use a suitable aperture.
 
ian-83 said:
Been looking to get into taking landscape photography a bit more and first on my list is a good tripod, but having a look about at a few articles about technique etc,. I have noticed a general suggestion is to focus about 1/3rd of the way into the scene. I currently using 4/3rds system but my lens has no depth of field scale on the lens. Will this cause issues? I have seen on things like Canon and Nikon lenses they have the depth of field scale on the lens which I guess makes setting up the lens in manual focus easier?
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Focusing 1/3rd in is a rough approximation that only works at fairly close distances, like groups of people. Anything else, and depth-of field varies anywhere between 50:50 and 1:millions.

For landscapes, the most useful method is usually hyperfocal distance focusing technique. It's actually very easy, you only need a few numbers jotted down inside your lens cap (get them from www.dofmaster.com ). Lots of threads on this. Although I have to say, with a wide-ish lens on 4/3rds format, pretty much everything will be sharp from quite near foreground to infinity, whether you want it to be or not ;)

ecoleman said:
Most distance scales on modern lenses are pretty useless for hyper focal distance anyway.
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You don't need a focusing distance scale on the lens for HFD technique - which is just as well, because most are useless.
 
Hyper schymper - I focus manually so it looks about right then use Live View to fine tune. Hyperfocal focusing is all well and good but I don't carry a tape measure in the field :-)
 
With Merklinger method you don't need DoF tables, but maybe a calculator (but not really :D)

I find lens markings a help. They may not be accurate but they can be a guide whereas fly by wire lenses don't offer anything unless you have an EVF and an in view indicator of some kind.

A lens with markings and end stops is IMO better though even if the markings aren't accurate.
 
Steve Smith said:
Then how do you know where you are focused?

Steve.
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You just need a simple HFD table, and the ability to estimate short distances in the 4-15ft kind of range, when using wide-ish lenses. HFD focusing isn't really practical with longer focal lengths, and exact measurements are not required. My HFD table has just a handful of numbers on it, stuck inside the lens cap of my 17-40mm lens, on full-frame. Focal lengths 17mm, 24mm and 35mm; apertures f/5.6, f/11 and f/22 - you can estimate inbetween settings accurately enough. Then you need to know that when HFD is set, sharp focus will extend from exactly half the HFD, to infinity.

So, decide on the nearest subject you want to be sharp, and estimate that distance - let's say 6ft. Then visually double that distance, ie 12ft, and using centre AF point, focus on a subject at that 12ft distance. That's HFD set. Then look inside your lens cap, and see what aperture is needed for a HFD of 12ft with the focal length you're using - answer f/5.6 with a 24mm lens, or f/11 with a 35mm lens, etc. Easy :thumbs:
 
Never really use the dof markings on my lens (elmarit 28 asph) although the markings do look quite good, and only ever look at the distance scale (prefer white meter to yellow feet scale) and the aperture scale.

I know that when aperture is set to 2.8 that dof will be narrow and 22 will be very wide so prefer trial and error rather than pedantically looking at the dof scale.
 
Most of my lenses have good DOF scales on them and my Rolleis have them on the focusing knob. No tables required.


Steve.
 
Cheers for all the replies. Guess I'll have a good go without worrying too much, use live view and find something approx 1/3 into the scene to focus on.
 
ian-83 said:
Cheers for all the replies. Guess I'll have a good go without worrying too much, use live view and find something approx 1/3 into the scene to focus on.
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Forget about this focusing on 1/3 into the scene!!!

Focus on the main subject area, set the aperture accordingly.

And what's live view got to do with the price of cheese??
 
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odd jim said:
Forget about this focusing on 1/3 into the scene!!!

Focus on the main subject area, set the aperture accordingly.
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Which isn't great advice as you may well land up unnecessarily using an aperture that is less sharp to achieve an unnecessary dof!
 
As Terry says. A lens will only be in focus at one point (physics). Stopping the lens down increases the level of acceptable or apparent sharpness in front of and behind this point.
Scales are based on some arbitrary notion of what is acceptable which may or may not coincide with how the image is to be output.
 
a1ex2001 said:
Which isn't great advice as you may well land up unnecessarily using an aperture that is less sharp to achieve an unnecessary dof!
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Only if you're a buffoon! How could that be, if you know what you're doing technically? You'd select an aperture, ISO and shutter speed to achieve what you're after.
 
Graham W said:
As Terry says. A lens will only be in focus at one point (physics). Stopping the lens down increases the level of acceptable or apparent sharpness in front of and behind this point.
Scales are based on some arbitrary notion of what is acceptable which may or may not coincide with how the image is to be output.
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This is true, depth-of-field is based on acceptable sharpness, not optimum sharpness, but the numbers are not arbitrary. The whole thing is based on the fact that the smallest detail we can discern is 0.2mm wide in a 12in print held at a distance equal to the length of the diagonal, ie about 15in. All DoF calcs are worked back from that assumption. This standard also holds good for any size of image, so long as the diagonal viewing distance is maintained. Also, it is a universal standard that's been used for decades. But if you change the viewing distance, such as viewing 100% on screen, or taking a close look at a large exhibition print, then the whole concept falls down. By the same token, if an image is cropped, that changes things too.

By definition, HFD technique puts both the closest subject and furthest distance right at the limit of acceptable sharpness and in practise best sharpness is somewhere around the near foreground. This may not be what's wanted and leads to landscapers using different methods - but they're all a compromise of some sort. (Using a tilt & shift lens is less compromised, hence their popularity with keen landscapers.) Bear in mind that while DoF tables are very exact (they have to be, to make the maths work) in practise sharpness doesn't just stop at a certain distance, but reduces gradually so you don't need a tape measure. The other thing is that the DoF standard we all use is a bit slack if it's highest quality exhibition quality prints you're after, though if you can use one f/number higher than the tables suggest, that's worth trying (so long as it doesn't take things too far into diffraction, say above f/11).
 
HoppyUK said:
By definition, HFD technique puts both the closest subject and furthest distance right at the limit of acceptable sharpness and in practise best sharpness is somewhere around the near foreground. This may not be what's wanted and leads to landscapers using different methods - but they're all a compromise of some sort. (Using a tilt & shift lens is less compromised, hence their popularity with keen landscapers.) Bear in mind that while DoF tables are very exact (they have to be, to make the maths work) in practise sharpness doesn't just stop at a certain distance, but reduces gradually so you don't need a tape measure. The other thing is that the DoF standard we all use is a bit slack if it's highest quality exhibition quality prints you're after, though if you can use one f/number higher than the tables suggest, that's worth trying (so long as it doesn't take things too far into diffraction, say above f/11).
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Once a lens is diffraction limited It does not get worse... But Depth of field still continues to increase with aperture.
Landscapers and others, of the old f64 school used this factor to get absolute maximum depth of field in their work. The fact that it was not as critically sharp, at point of focus, as when set at say f5.6 was an advantage as all parts of the image were equally very sharp but with no area of critical focus.
was no concern to them. as mostly they were using large format with relatively small enlargement, even when making 20x16 prints.
The softness was to some extent compensated for. by using a (beutler type) developer that increased outline contrast( actuance) Or more often by simply increasing the contrast slightly.
Many large format lenses went down as far as F128. and were regularly used in high quality architectural photography.

Today we view sharpness differently, as we check our images for sharpness at maximum magnification rather than the more realistic large print on the wall method.
 
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Terrywoodenpic said:
Today we view sharpness differently, as we check our images for sharpness at maximum magnification rather than the more realistic large print on the wall method.
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Exactly. And if it doesn't end up as a large print on the wall, it probably doesn't matter.


Steve.
 
Terrywoodenpic said:
Once a lens is diffraction limited It does not get worse... But Depth of field still continues to increase with aperture.
Landscapers and others, of the old f64 school used this factor to get absolute maximum depth of field in their work. The fact that it was not as critically sharp, at point of focus, as when set at say f5.6 was an advantage as all parts of the image were equally very sharp but with no area of critical focus.
was no concern to them. as mostly they were using large format with relatively small enlargement, even when making 20x16 prints.
The softness was to some extent compensated for. by using a (beutler type) developer that increased outline contrast( actuance) Or more often by simply increasing the contrast slightly.
Many large format lenses went down as far as F128. and were regularly used in high quality architectural photography.

Today we view sharpness differently, as we check our images for sharpness at maximum magnification rather than the more realistic large print on the wall method.
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The F64 Group used (very) large format cameras, like 10x8in. Diffraction is simply not an issue with them, even at f/numbers like f/64, f/90 etc that our (relatively) tiny format DSLRs cannot even get near. Plus they have tilt & shift movements to optimise DoF. Completely different, frankly irrelevant to DSLR working.

But if you're shooting on a crop format APS-C sensor then f/22 is to be avoided if you want best sharpness, and IMHO f/11 is about the limit (f/16 on full-frame). It's all a compromise though, you can't have everything, and if you're running out of sharpness at near and far distances with HFD technique, generally speaking you'll gain more by stopping down further than you'll lose to diffraction - as you say.
 
HoppyUK said:
But if you're shooting on a crop format APS-C sensor then f/22 is to be avoided if you want best sharpness, and IMHO f/11 is about the limit (f/16 on full-frame). It's all a compromise though, you can't have everything, and if you're running out of sharpness at near and far distances with HFD technique, generally speaking you'll gain more by stopping down further than you'll lose to diffraction - as you say.
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To me you have to consider the final image size and viewing, be it screen or print. If you want a very large image and intend to view closely and be very critical then small apertures are possibly going to offend :D but for many uses small apertures can be used and no one will complain. Certainly I've shot at f16 with micro four thirds and people have liked the shot. The theory for us anal geeks says avoid these apertures but in the more real world the results can and are often very good to the person viewing the image if they and the viewing circumstance aren't at the extreme :D.
 
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